2 Corinthians 13:13
“Salute one another with an holy kiss,” he added, “All the saints salute you.”
By this also giving them good hopes. He has added this in the place of the kiss, knitting them together by the salutation, for the words also proceed from the same mouth from which the kiss. Do you see how he brings them all together, both those who are widely separated in the body and those who are near, these by the kiss and those by the written message?
Source: Homilies on Second Corinthians (New Advent)